The present application relates to an information storage element employing a magnetic material and a method for driving the same.
In an information apparatus such as a computer, a hard disk is widely used as an external storage device.
However, because the hard disk involves a rotational mechanism, size reduction and power saving thereof are difficult.
An SSD (solid state drive) employing a flash memory has begun to be used as an external storage device for a small apparatus. However, the price thereof is high and the storage capacity thereof is also insufficient. Furthermore, there is a limit to the number of times of recording, and there is a limit to the use thereof as an external storage device.
Thus, a non-volatile storage device that has high storage capacity and is capable of high-speed reading and writing is desired.
As a candidate for the non-volatile memory, magnetic memories to record information as magnetization of a magnetic material are attracting attention and development thereof is being promoted. Among the magnetic memories, an MRAM that reverses the magnetization direction by a current magnetic field (e.g. MR2A16 made by Freescale Semiconductor, Inc.) has been put into practical use.
As a magnetic memory having higher density, attention is being paid to a configuration in which a current magnetic field is not used but a current is made to flow between two magnetic materials sandwiching a non-magnetic material and spin-injection torque working between them is utilized (e.g. refer to Japanese Patent Laid-open No. 2003-17782 and F. J. Albert et al., Appl. Phys. Lett. Vol. 77, No. 23, 2000, p. 3809). The magnetic memory having this configuration is called a spin-torque MRAM or a spin RAM.